Various techniques have been proposed for the separation of carbon dioxide from gas mixtures. For example, Winnick, J., Marshall, R., and Schubert, F., “An Electrochemical Device for Carbon Dioxide Concentration. I. System Design and Performance,” Ind. Eng. Chem., Process Des. Develop., Vol. 13, No. 1, 1974, pp. 59-62, describes the use of electrochemical cells for carbon dioxide concentration. These and similar methods use electrochemical or “polarization membranes.” These membranes operate on the principle that CO2 is converted to soluble carbonates at high pH and is liberated again at low pH. CO2 is preferentially absorbed on the basic side and released on the acidic side.
It would be advantageous to have improved techniques to separate a gas from a mixture of gases.